Iguanas: Diseases

By Gregory Rich, DVM; Rick Axelson, DVM

What are some common diseases of pet iguanas?

When iguanas are in a suitable environment, given a good diet and have exposure to UV (ultraviolet) light, they are reasonably hardy animals. Common conditions of pet iguanas include metabolic bone disease, fungal skin infections, infectious stomatitis (mouth rot), external (skin) and intestinal parasites, respiratory disease, and hypervitaminosis D.

What are the signs of these diseases?

Metabolic bone disease (MBD) is a complex disease and is probably the most common medical problem of pet iguanas. It is typically caused by feeding an improper diet that is high in phosphorus and low in calcium or vitamin D3 (from a nutritional deficiency), or from either a lack of UV-B lighting or a lack of exposure to natural light. Common signs include swelling of the lower jaw, softening of the jaw and facial bones (rubber jaw), and/or swelling of the hind limbs. X-rays reveal thin bone tissue (decreased density), widened and thickened bone shafts and possibly fractures that appear to have happened with minimal force or for no apparent reason. Green-stick or folding fractures may occur in soft bones that appear to bend or fold and not fully break apart. Blood tests may show either a low calcium level or an elevated phosphorus level. The diagnostic feature is an abnormal calcium to phosphorus ratio. A normal calcium:phosphorus ratio is 2:1 or 3:1. As the condition progresses, muscle twitching, seizures, loss of appetite, and loss of energy (lethargy) are seen. MBD is also known as fibrous osteodystrophy or nutritional secondary hyperparathyroidism. It is most commonly seen in juvenile iguanas (less than 2 years old).

A common fungal skin infection that infects mostly young iguanas is a disease called CANV which stands for Chrysosporium Anamorph of Nannizziopsis Vriesii. It is often referred to as Yellow Fungus Disease. Visually, the disease causes tan to yellow crusty skin lesions anywhere on the body. Advanced cases may show open bloody skin lesions. Treatment requires several weeks of a prescription antifungal medication and in some cases, may be fatal.

Infectious stomatitis (mouth rot) is a bacterial infection that manifests as pinpoint hemorrhages on the gums, swollen gums, or an excess production of thick mucus (often looking like cottage cheese) in the mouth. Mouth rot can also cause swelling of the jaw just like MBD. In the case of swelling along the gumline or along the jaw bone, a solid abscess has most likely formed in the soft tissue of the gums.

"Mouth rot can also cause swelling of the jaw just like MBD."

Intestinal parasites, especially pinworms, are common in pet iguanas. They often cause no clinical signs and are detected on an annual fecal examination. In some cases, they may cause diarrhea or weight loss. Pinworms are probably commensal organisms (commensalism is an association between two organisms in which one individual benefits from the relationship while the other is neither benefited nor harmed). Mites and ticks are sometimes found on the skin of your iguana. They are spread by direct contact with infected iguanas and are not from other pets or the cage environment. Mites and sometimes ticks can be visibly seen moving around, under or between scales around the head, legs, and in skin folds.

Respiratory infections or pneumonia can occur in animals that are stressed, improperly fed, or kept in poor, cold, or dirty conditions. You may see sneezing, nasal or ocular discharge, bubbles in the mouth, unnaturally rapid or shallow breathing, pulling or gasping for breath, and lethargy (lack of energy).

Hypervitaminosis D is a condition that develops when owners either over-supplement the iguana's diet with vitamins and minerals, or feed it dog or cat food. Clinical signs are vague and include lack of appetite and lethargy.

How can I tell if my iguana is sick?

Signs of disease in iguanas may be specific for a certain disease, such as jaw or hind limb swelling with MBD. Any change in skin color or texture should be brought to the attention of a veterinarian knowledgeable in reptile medicine.

"More often, signs of disease are non-specific"

More often, signs of disease are non-specific, such as an iguana with anorexia (lack of appetite), depression and lethargy, which can be seen with many diseases. Any deviation from normal is cause for concern and your iguana requires immediate evaluation by your veterinarian.

How are iguana diseases treated?

Any of these diseases can be severe enough to cause a loss of appetite and/or severe lethargy. Conditions of noticeable health issues need examination by a veterinarian knowledgeable in reptile medicine. Your iguana may require hospitalization and intensive care, which can include medications, fluid therapy, and force-feeding.

Metabolic bone disease usually requires immediate treatment with injectable or oral calcium, a multivitamin or mineral supplement, and/or calcitonin, a drug that promotes calcium uptake into your iguana's bones. Long-term management of MBD requires dietary modification and balancing, and provision of UV-B lighting.

A diagnosis of CANV will require oral anti-fungal and/or oral antibiotic therapy. Treatment may take weeks to months to resolve.

Infectious stomatitis (mouth rot) usually requires injectable antibiotics, as well antibiotic mouth rinses. Severe cases may require surgery to remove abscessed tissue.

Several deworming medications are available either as an oral or injectable drug. The type of parasite identified on the microscopic fecal examination will determine which drug is needed. Mites and ticks can be treated either topically or with oral or injectable medication as directed by your veterinarian. Environmental cleaning, disinfecting, and treatment may be needed as well.

Respiratory infections will be investigated with x-rays, blood tests, and cultures. They will likely be treated with oral or injectable antibiotics. If they are severe, the animal will have to be hospitalized for more aggressive therapy and support.

Hypervitaminosis D is a serious problem that requires hospitalization and intensive therapy with fluids, force-feeding, and drugs to help lower the iguana's calcium level. Dietary modification is necessary for long-term treatment.

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